The metal-working industry, in order to accomplish shaping processes on metals, no matter whether they are made by cutting or non-cutting, needs coolants which facilitate the shaping processes and which, in particular, are in a position to eliminate the heat energy occurring, and to simultaneously and subsequently protect the shaped metal from corrosion.
As is well known, such agents are generally called cooling-cutting compounds or cooling lubricants. The development of these cooling - cutting compounds was particularly rapid during the past decade, because of the general tendency toward automation of the finishing processes. This rapid development led to products which in their essence and composition may be defined as colloid-dispersed systems of non-saponifiable mineral oils in mixture with surface-active substances in water.
As a result of automating the production within the metal-working plants, it has become necessary to depart from the formerly customary use of pure mineral oil emulsions, which had been prouced from petroleum sulfonates and mineral oils, since these mineral oil emulsions no longer satisfied the rising demands. On the one hand, these mineral oil emulsions, because of their high content of mineral oil, had only a poor or unsatisfactory cooling effect. On the other hand, these mineral oil emulsions, because of their low capacity for dilution with water, also had only a poor or unsatisfactory corrosion protection property. A third disadvantage of these mineral oil emulsions was their low resistance against micro-organisms. This resulted in the undesirable formation of decaying substances, odorous annoyances and a high strain on the environment.
The development of better cooling - cutting agents, which contained less mineral oil and resulted in less of a strain on the environment, led to the use for the first time of complex soaps of ethanol amines with natural fatty acids. These agents were obtained by special processes under the influence of boric acid at temperatures between 230.degree. and 200.degree. C. These new cooling-cutting agents were used with great success in the metal-working industry. For example, in metal processing or metal forming plants, in which the former coolants could be kept only a few weeks with the addition of preservatives, operating lifetimes of 30 weeks and more were achieved with the above described novel products, without there being any need of adding preservatives. This advantage along provides a tremendous decrease in the costs, and enables a manifold increase in the effects of automation. Furthermore, the skin allergies of the workers, caused by the preservatives used, disappeared completely when the above described novel products were substituted.
It was further observed that using the above mentioned novel cooling-cutting agents (representing colloidal-disperse systems) allowed one to carry out cutting operations on highly alloyed steels for airplane turbines; up to that time these operations had not been achieved and were not even considered possible.
Therefore, these new, above described cooling - cutting agents have been found very satisfactory for numerous applications.
However, in considering particular technical applications it became apparent that certain disadvantages still existed for certain areas of usage which could not be eliminated by the use of the above described prior art cooling-cutting agents.
The reason for the problems with the prior art agents is that all known fatty acids form line soaps which lead to deposits. These deposits in turn, together with the mineral oil coming from the machines, lead to residues. These residues are not removable or are removable only with great difficulty because of their insolubility in water.
These problems at first seemed insignificant but lately they have acquired extraordinary importance in practice. The problems are especially significant in the case of machines and finishing processes that are controlled numerically. Their manufacturing output may be interrupted or even stopped by the adherence of a small metal splinter to the slideways.
Furthermore, the precipitated lime soaps, which may be deposited in the supply line systems, form a nutrient medium for microorganisms. These microorganisms consume the organic components of the lime soaps and leave insoluble calcium oxide or insoluble calcium carbonates behind. These lime deposits, which then solidify in the pipe line systems, lead to the pipe lines becoming radially shut from the outside of the pipe lines towards the inside and eventually plugging up the pipe lines completely.